Enantioselective Synthesis of Vicinal Halohydrins via Dynamic Kinetic Resolution

Expanding the scope of enantioselective catalysis via DKR, transfer hydrogenation of a variety of cyclic α-halo ketones was accomplished using the Noyori/Ikariya (R,R)- or (S,S)-I catalysts and either HCO2H/Et3N or HCO2Na/n-Bu4NBr in H2O/CH2Cl2 as the hydrogen sources. Good yields of vicinal bromo-, chloro-, and fluorohydrins with excellent de and ee levels were achieved in most cases after a simple tuning of reaction conditions.